High performance computer systems may utilize multiple processors to increase processing power. Processing workloads may be divided and distributed among the processors, thereby reducing execution time and increasing performance. One architectural model for high performance multiple processor system is the cache coherent Non-Uniform Memory Access (ccNUMA) model. Under the ccNUMA model, system resources such as processors and random access memory may be segmented into groups referred to as Locality Domains, also referred to as “nodes” or “cells”. Each node may comprise one or more processors and physical memory. A processor in a node may access the memory in its node, sometimes referred to as local memory, as well as memory in other nodes, sometimes referred to as remote memory.
Multi-processor computer systems may be partitioned into a number of elements, or cells. Each cell includes at least one, and more commonly a plurality, of processors. The various cells in a partitioned computer system may run different operating systems, if desired. Typically, each partition runs a single operating system.
Many computer systems provide the ability to remove or eject hardware devices from the computer system. For example, some computer systems implement the Advanced Configuration and Power Interface (ACPI), which provides a method to remove hardware resources from an operating system while the operating system is running. This is sometimes referred to as a “hot” removal. In systems that implement the ACPI, system firmware may track which devices are removable and maintain status information relating to those devices.
In some circumstances, it may be useful to move one or more resources from one partition to another partition in a multiprocessor computer system. For example, most computer systems have multiple memory devices, ranging from cache memory to main memory devices including random access memory (RAM) devices (e.g., dynamic RAM or static RAM devices) as well as other types of memory such as read only memory (ROM) devices or external memory devices. In some computer systems, not only specific devices but also memory portions or locations within the various hardware devices also potentially are divisible and potentially allocable. Also for example, most computer systems have one or more processing devices (e.g., central processing units (CPUs) such as microprocessors), and the processing power of these devices can allocated to different processes.
In some computer systems the allocation of resources to the multiple processes of such conventional computer systems is rigidly fixed, either permanently when the computer systems are built or when the computer system are turned on or rebooted. Such rigid allocation of resources can be undesirable, since the needs of the processes can change over time during their operation.